diff --git a/libraries/AP_HAL_SITL/GPIO.cpp b/libraries/AP_HAL_SITL/GPIO.cpp
index 6b2500bbfa..1f493f7907 100644
--- a/libraries/AP_HAL_SITL/GPIO.cpp
+++ b/libraries/AP_HAL_SITL/GPIO.cpp
@@ -11,11 +11,6 @@ void GPIO::init()
 void GPIO::pinMode(uint8_t pin, uint8_t output)
 {}
 
-int8_t GPIO::analogPinToDigitalPin(uint8_t pin)
-{
-    return pin;
-}
-
 uint8_t GPIO::read(uint8_t pin)
 {
     if (!_sitlState->_sitl) {
diff --git a/libraries/AP_HAL_SITL/GPIO.h b/libraries/AP_HAL_SITL/GPIO.h
index 7c36ccf502..acd24a2172 100644
--- a/libraries/AP_HAL_SITL/GPIO.h
+++ b/libraries/AP_HAL_SITL/GPIO.h
@@ -7,7 +7,6 @@ public:
     explicit GPIO(SITL_State *sitlState): _sitlState(sitlState) {}
     void init();
     void pinMode(uint8_t pin, uint8_t output);
-    int8_t analogPinToDigitalPin(uint8_t pin);
     uint8_t read(uint8_t pin);
     void write(uint8_t pin, uint8_t value);
     void toggle(uint8_t pin);